MAGNETIC RESONANCE IMAGING PROVIDES USEFUL DIAGNOSTIC INFORMATION FOLLOWING EQUIVOCAL ULTRASOUND IN CHILDREN WITH SUSPECTED APPENDICITIS

Transcription

1 Department of Pediatrics MAGNETIC RESONANCE IMAGING PROVIDES USEFUL DIAGNOSTIC INFORMATION FOLLOWING EQUIVOCAL ULTRASOUND IN CHILDREN WITH SUSPECTED APPENDICITIS Graham Thompson MD FRCPC, Dori Ann Martin BScN, Rory Killam BEd, Robin Eccles MD FRCSC, Mary Brindle FRCSC, Priya Gupta MD FRCPC for the Alberta Sepsis Network Appendicitis Working Group

2 DISCLOSURE I have no financial conflicts to disclose 2

3 BACKGROUND Thompson GC, Schuh S, Liu H, Gravel J, et al. Variations In The Diagnosis And Management Of Appendicitis At Canadian Pediatric Hospitals Acad Emerg Med. In Press

4 BACKGROUND the appendix could not be completely visualized acute appendicitis can not be ruled out clinical correlation is required Ross MJ, Liu H, Netherton SJ, et al. Outcomes of Children With Suspected Appendicitis and Incompletely Visualized Appendix on Ultrasound. Acad Emerg Med. 2014;21(5):

5 BACKGROUND

6 BACKGROUND IDAC Improving Diagnostics for Appendicitis in Children Clinical Scores Alvarado, PAS, Lintula Metabolomics and Luminex cytokine analysis blood + urine MRI Appendiceal measurement of histones.

7 OBJECTIVES To quantify the magnitude of additional diagnostic information provided by MRI in children with SA and equivocal US.

8 OUTCOMES OF INTEREST Primary outcome measure proportion of children with equivocal US studies in which a positive or negative diagnosis was determined by MRI. Secondary outcome measures proportion of children with common MRI findings of appendicitis in those with equivocal US agreement between MRI results and pathology.

9 METHODS Study Setting, Design and Population Single Centre Alberta Children s Hospital Prospective cohort study Inclusion Criteria Age 5 to 17 years Presenting to a tertiary pediatric Emergency Department (ED) with Suspected Appendicitis Ultrasound for? appendicitis Surgical consult for? Appendicitis IV in place or IV/blood work to occur Exclusion Criteria Requires PICU admission Previous Appendectomy or other major abdominal surgery Pregnant Abdominal pain > 5 days Immune disorder Language barrier Transfer from another site with positive imaging Previous enrolment.

10 METHODS Study Process

11 METHODS Study Process Historical and clinical data forms IDAC study samples drawn blood and urine MRI Timing Fluid 4 hour guideline No sedation No contrast

12 METHODS Study Process Siemens Avanto 1.5 Tesla scanner. Reported by a sub specialty pediatric radiologists No appendicitis Acute Appendicitis Equivocal for Appendicitis Blinded to clinical information Blinded to US result. MRI NOT part of clinical care

13 Followed throughout hospital stay Followed for return ED visit within 7 days Health Record review METHODS Study Process Definition of Appendicitis Independent pathologist Reviewed and classified clinical pathology reports Normal, Acute Appendicitis, Ruptured Appendicitis No evidence of management for appendicitis = normal

14 RESULTS 140 Enrolled 101 MRI 0PercDrain 0 NOMAs 45 D/C Home 53 Admit Sx 3 Admit Peds 0 Appendectomy 40 Appendectomy 1 Appendectomy 38 Appendicitis 1 Appendicitis

15 RESULTS Patient Characteristics n = 101 Female (%) 57 (56.4%) Age, average (SD) 11.9 (3.4) Previous HC visit (%) 5 (49.5%) PAS, median (IQR) 6 (4) US performed (%) 98 (97.0%) CT performed (%) 8 (7.9%) Appendectomy (%) 41 (40.6%) Appendicitis (%) 39 (38.6%) Perforation Rate 24.4% (10/41) Negative Appendectomy Rate 4.9% (2/41)

16 RESULTS Ultrasound 98 Ultrasound 53 (54.1%) equivocal 32 D/C Home 21 Admitted 5 (15.6%) RTED 8 (38%) Appendectomy 1 Admit Abdo Pain NYD

17 RESULTS MRI vs Ultrasound Ultrasound Impression MRI Impression Negative Equivocal Positive Total Negative 10 (83.3%) 2 (16.7%) 0 12 equivocal 31 (58.5%) 12 (22.6%) 10 (18.9%) 53 Positive 2 (6.1%) 2 (6.1%) 29 (87.9%) 33 Total MRI provided Diagnostic Information in 41/53 (77.4%) of Equivocal US.

18 RESULTS MRI vs Ultrasound Equivocal Ultrasound Impression MRI Impression Negative Equivocal Positive Total Female 22 (71.0%) 4 (12.9%) 5 (16.1%) 31 Male 9 (40.1%) 9 (36.4%) 5 (22.7%) 22 Result more apparent in Females 27/31 (87.1%) vs 14/22 (63.6%) p = 0.04

19 RESULTS MRI vs Ultrasound Additional Information Provided by MRI for Equivocal US (n = 53) Appendix Seen on MRI 39 (73.6%) Peri appendicular Fluid 12 (22.6%) Intraluminal Fluid 9 (17.0%) Fat Stranding 8 (15.1%) Appendicolith 2 (3.8%) Abscess 1 (1.9%) Free Fluid trace only 24 (45.3%) 10 (18.9%) Formal Diagnosis (+ or ) 41 (77.4%)

20 RESULTS MRI vs Pathology Report Pathology Report MRI Impression Negative Equivocal Positive No Appendicitis Appendicitis Of the 4 False Positives 3 had equivocal US, 1 did not have an US. 2 were discharged from the ED based on clinical exam, both of who returned to the ED but were again discharged home 2 were discharged by surgery after a period of observation, none returned.

21 RESULTS MRI vs Pathology Report Pathology Report MRI Impression Negative equivocal Positive No Appendicitis Appendicitis MRI Neg 14 yo M, PAS = 3 WBC = 6.6 N = 2.9 CRP = 32 8 mm on US 6mm, mild intraluminal fluid (MRI) 1 MRI equivocal 11 yo M no labs done 10 mm on US 7.2 mm, mild peri appendicular fluid (MRI)

22 RESULTS MRI vs Pathology Report Pathology Report MRI Impression Negative Positive No Appendicitis 58 4 Appendicitis 2 37 Sensitivity = 94.9% ( ) Specificity = 93.5% ( ) PPV = 90.2% ( ) NPV = 96.7% ( ) Observed Agreement = 94.1%

23 LIMITATIONS Sample Size Part of an overarching study aimed at improving diagnostics in appendicitis Timing of symptom onset has not been evaluated, but the data is available. Inter observer reliability multiple DI readers, single read of each MRI and US study Single pathologist classifying based on pathology report MRI availability significant limited.

24 CONCLUSIONS In children with SA and equivocal US, MRI can provide emergency and surgical clinicians substantial additional diagnostic information, without the risk of ionizing radiation from CT. The addition of MRI in clinical pathways/guidelines for the evaluation of children with SA should be considered Further economic, feasibility and generalizability studies are warranted. Comparison of ED MRI vs admit for observation. Comparison of next day MRI vs repeat exam in am Comparison of next day MRI vs repeat US in am

25 ACKNOWLEDGEMENTS Alberta Sepsis Network Alberta Innovates Health Solution Pediatric Emergency Research Team (PERT) Pediatric Emergency Medicine Research Associate Program (PEMRAP) ACH PED physicians

26 ACKNOWLEDGEMENTS ASN Appy Working Group Jaime Blackwood MD FRCPC Pediatric Intensive Care, University of Calgary Mary Brindle MD FRCSC Pediatric Surgery, University of Calgary Robin Eccles, MD FRCSC Pediatric Surgery, University of Calgary Priya Gupta MD FRCPC Pediatric Diagnostic Imaging, University of Calgary Craig Jenne PhD Snyder Translational Laboratory, University of Calgary Ari Joffe MD FRCPC Pediatric Intensive Care, University of Alberta Ijab Khanafer MD Pediatric Resident, University of Calgary Beata Mickiewicz PhD Metabolomics Research Centre, University of Calgary Clara Ortiz MD FRCPC Pediatric Diagnostic Imaging, University of Calgary Nusrat Shommu MSc Metabolomics Research Centre, University of Calgary Kathy Tobler MD FRCPC Pediatric Intensive Care, University of Calgary Hans Vogel PhD Metabolomics Research Centre, University of Calgary Wieming Yu MD FRCPC Pediatric Pathology, University of Calgary